Install Electronic signature Word Android

Edit: I wrote this answer for “must have Android apps” but these are same apps which have changed the way I used to live my life. Each and every App has helped me in one or the other way. I hope you will also find them helpful and a bit life changing. So here is the list: 10. Psiphon For those who use WiFi with proxy settings. So Psiphon bypasses and tunnel the websites or app through a different IP Address. 9. Mirror It's a simple app to record your mobile screen. Based on the concept of CamStudio in PC where you can record your screen, Mirror offers recording of your Mobile screen. 8. NTES- National Train Enquiry System If you are from India and you want to know the running status, cancelled train (partial or fully), Live Station and other features, this App is a must have. 7. VOLT Simple but effective for those who want to learn new vocabulary. That's too obvious, then why not others? Coz here you get the “memory key” which helps you relate the words and easier to remember them. 6. Parchi It a note making app. But here’s a catch. You can view, review, edit and add right from your lockscreen without need to open the app. Isn't that amazing! I personally find this app very useful. 5. edX If you are student or a learner who wants learn something new everyday, and cannot afford to go in the prestigious institutions like MIT, Harvard University, Cambridge, IITM, etc ten it is a must have app. Enroll yourself in any course and Bazinga!! You are ready to learn from the most amazing professors. Similar to edX, we have Coursera. 4. Walnut Manage your expenses on your finger tips. Its easier then that. It shows you your monthly expenditure, ATM locations, bill remainders and many more features. Its a must have app. 3. CamScanner Everyone doesn’t own a scanner but most of us have camera. So click the pic, upload to CamScanner and voila you are done. You have the scanned copy of your documents, notes, Marksheet and upload them on your DigiLocker. 2. inshorts Till now you all must be knowing this app. The tagline is also simple “News in 60 words” and trust me it is worth having. In this “I don't have time” world, you need news to be fast and accurate so here it is. 1. DigiLocker If you have this app then you don’t need to carry your personal documents like driving license, Adhar card, voter ID card, or even your Marksheets. Keep them safe in actual locker and leave the rest to your DigiLocker. And the best part is that it is acceptable as the original ones at every governmental or non governmental institution because it is developed under Digital India initiative. That's it for the day. Thank you and Enjoy !!! Update 1: Today I came across two new apps which I found useful. Hope it would help you all. 1.Forest : Stay focused Features • A self-motivated and interesting way to help you beat phone addiction • Stay focused and get more things done • Share your forest and compete with friends • Track your history in a simple and pleasant way • Earn reward and unlock more tree species • Customize your whitelist : Leaving Forest and using apps in whitelist won’t kill your tree. 2. Swachh Bharat Toilet Locator Swachh Bharat Toilet Locator is specifically useful for Indians who're committed for Swachh Bharat. Update 2: So I am back with yet another interesting app for you all. And trust me it is worth hanving. You are bored just go through it and kaboooom !!! You are into a black hole. Enjoy the ride. 3. Curiosity It is the latest app I installed but got addicted to it. It’s exactly works like its name, generates a curiosity which inturn increases your knowledge. It covers a large field of scope from Humanity to science to faith and many more. This app deserves more snapshots but why to increase the length of my answer. Comment below if you think the list should be updated? Thank you.

This is not an “answer” but an analysis of the range of answers given. “Hate” is an exaggeration as the factors forwarded are merely annoyances or unexpected differences; readers from less developed nations would label the laments as “Rich Country Concerns” (i.e. petty for most people). My answer is based on decades of life and travel in Western Europe - not Eastern Europe.The major gripes are that things are not as “convenient”, dimensions are small, people are “unfriendly” and the customer is not “always right” in Europe. Let’s see if those “complaints” are worth writing home about or if ...

Warning long answer!Since 1990, I’ve been studying the confidentiality of the messaging systems on computers and mobile devices.It was obvious that the electronic forums, emails and SMS messages could easily be intercepted by 3rd parties. Expecting the service providing companies to develop and implement confidentiality protocols were unrealistic. There were never a general consensus about the need for confidentiality or inter-service protocol development.With the discouragement of the governments many computer scientists shied away from creating software to keep communication confidential between parties.Many spy movies showed advanced technologies to keep the communication between spies and their organizations. The most famous being the Enigma machine used by the Germans during the World War 2. British scientist Alan Turing was the one to develop an early version of today’s computers to solve the mystery of the Enigma machine. Like every visionary he had serious problems with the establishment. After the government discovering that he was gay, he was given 2 options. First option was jail time until he turned heterosexual, or chemical castration. Poor Turing chose the second option and after a while he committed suicide. Every cryptologist today remembers to what happened to the first representative of this science.Without getting into the technological terms (they are all available on Wikipedia) the best way to keep conversation confidential is to use a code book between 2 (or more, but more on that later) parties. A code book is a simple definition and a list of codes that is shared between the parties and each code is used only once. Unless the code book is compromised this method of communication privacy is bullet proof. There is no computer in the world, and there won’t be any in the future that can figure out what the communication is. The only method would be the old school spying on the parties who are communicating between each other.If I need to give an example for the method above, it would be like, let’s choose a newspaper that is accessible to both parties. That will be our message base.Let’s define a codebook now:First code in the book is3–4,6–7,1–2 and repeats itselfsecond code is5–7,3–1,8–5,4–2 and repeats itselfSo let’s say I send you a message today like20,42,15,5,8,67,23,56,12,43,13,11,10Since it is our first message exchange you will use the first code in the book. Also our message base is only known to us which also makes it even more difficult for others to understand the secret message I just sent you.To understand the message, here is what you do: you pick up today’s New York Times which is the newspaper we agreed to use.Take the first number in the secret message which is 20, then look in the codebook for the first code which is 3–4. You go to the 3rd page find the 4th paragraph and get the 20th character and repeat this process for each number in the secret message I sent.Let’s say MI6 is trying to intercept the message, which they do because I sent the message by email or SMS or event with both to you.All they have is 20,42,15,5,8,67,23,56,12,43,13,11,10 and they have no idea what it means. They don’t know which text source we used, which was New York Times and they don’t know the code we used for that message which was 3–4,6–7,1–2. We can even make this more difficult, for each day of the week we use a different newspaper that we agree upon.And let’s say MI6 figures out which newspaper we use for each day, let’s say they even figure out our code mechanism which is the page, paragraph and character to decode the secret message.As long as we use each line of code only once and never repeat used codes, there is virtually no way that MI6 to figure out our conversation. Except of course sending their double o agent to one of us and beating us in the head with an iron bar which would make us sing like a bird and spill all the secrets.As you can see in the example an iron bar, strategically placed on your head with a moderate blow would break all the code we established.That reality aside, if I whisper to your ear the newspaper names and hand you a piece of paper with a list of codes which I also have the same copy, until ve run out of codes there is no way our communication can be interpreted when intercepted.The difficulty in this type of message confidentiality is sharing and keeping a piece of paper with a list of codes and do the code exchange again when the list of codes are depleted and never use a code again.When this is not possible for practical reasons like distance between parties or the number of messages exchanged being too high and frequent the methodology used is computer based encryption (ensuring the confidentiality of communication between parties) of messages.This is also not so unlike what we did in the first example. To create our never ending codes is that for each message we exchange we use 3 constants. You have a master key, a public key and we agree on a mathematical formula which is very very difficult for the computer to solve. The difficulty here ensures that the time to try every combination of variables (without the master key) for the formula is so long, it practically makes it impossible for others to guess our code list.In this method I also have a master key and a public key. To solve the issue of keeping a list of established codes and communicating that between parties we freely exchange our public keys with everyone and when I’m sending you a message, I use your public key (any of my keys except generating a special signature with my private key so that you can validate with my public key that ensures the message has originated really from me) to create a confidential message. When you receive it by email, SMS or regular post mail, you use your private key which can only find out the contents of the confidential message. And since we are talking about computer systems, we protect our private keys with passwords.I don’t like using names given by computer engineers or any other technical person but for the sake of clarification this master/public key and an established algorithm to use is called public private key cryptology.Another term I don’t like is ‘end to end encryption’. This is to confirm that the cryptology method used can not be intercepted by other parties and only the recipient can understand the contents of the message.One company who has developed an implementation of end to end encryption is Open Whisper Systems. They named their product ‘Signal’ which is a platform and also the name of their app on iOS and Android. Their product uses this public private key cryptology to ensure the text and voice communications between parties to stay confidential. Supposedly the infamous NSA whistle blower Edward Snowden uses their app and he considers it quite good.Now let’s circle back to the WhatsApp security issue. WhatsApp is using the protocol established by the Open Whisper Systems for their public private key protected communications (audio, video and text messages).The problem is the user friendliness of the Signal app is not good. There are certain times that these public and private keys have to be changed. 2 example of those times is if you change your phone or uninstall / reinstall your app (whichever app you are using, Signal or WhatsApp)To test the user friendliness of Signal App’s handling the change of the key pairs (public private key combinations) I used my regular human guinea pig Riz. It was very difficult for me to explain what he has to do and also to find the location of the menu items were horribly difficult. After cursing at me and the app designers many times Riz completed the approval of the new key exchange between us so we could communicate again.Let’s have a look into how WhatsApp has implemented this renewal of key pairs between users. Since authenticity of a user can only identified by trusting their private key signed signature and for the likely case of the user have a new phone or has reinstalled the WhatsApp App, WhatsApp servers keep a copy of the secret message until the recipient downloads it. Now let’s say that you sent me a message while I was offline and I changed phones meanwhile. When I get that message from you what the Signal app does is, it warns me and it won’t let you communicate with you until I approve your new public key (in the style of a combined public keys of both parties because there is only one code that needs to be verified on both ends). Instead of asking user to do the verification what WhatsApp does it re-encrypts your message with my new key again (in their explanation by asking your WhatsApp to keep that message in memory in encrypted form and first decrypt then re-encrypt the same message with my new public key) without asking neither of us to re-confirm the identity of both parties.This technically opens up a backdoor for intelligence agencies to decrypt the messages between parties.How does that happen? WhatsApp confirms App installation by SMS confirmation. Let’s say I want to intercept your WhatsApp messages. I send a team in a delivery van which looks like a repair van but which has a mobile communication signal jammer to your home address. The jamming is smart enough to make your phone think it is still in network coverage so you don’t suspect a thing unless you try to make a call which will look like mobile network is crowded and unavailable. While I knock your phone off the network I can do 2 things, I can either intercept any SMS messages which comes your way in my service van, or give a court order to the mobile phone company to give me a copy of your SMS messages in real time.Then I install WhatsApp on a new phone, enter your phone number as my number and receive a copy of the SMS confirmation with the verification number and enter it in WhatsApp. From that moment on I will receive any waiting (since I knocked you off mobile network) and any news messages WhatsApp users send to you.Intentional or unintentional this is a secret door that can be easily used by government agencies.If I used the above technique to intercept messages between Signal users, what would happen were to be, first I couldn’t receive any messages waiting in the cloud because Signal does not keep messages in the cloud, when you are offline, the message waits in the sender’s Signal App. When the sender tries to send a new or resend the unsent message to you, my new installation of Signal app on my government agency phone will inform your friend, the sender that I’ve changed our shared agreed secret code and asks your friend if s/he wants to approve this new installation on the other end by confirming the new shared secret code with you. When s/he calls you on your landline, you say you haven’t installed a new WhatsApp on your phone or changed phones, you both understand that there is another party in between trying to intercept your messages.Now, WhatsApp says that there is an option in their App, under Settings / Account / Security / Show Security Notifications which is by default off. If you turn this ON then their claim is you will receive notifications when a contact’s security code has changed. They don’t say if the messages will still be delivered in spite of a security notification or not. They add that ‘The messages you send your calls are encrypted regardless of this setting, WHEN POSSIBLE’. I capitalized the last 2 words, what the heck ‘WHEN POSSIBLE’ mean? They also do not say anything about the messages you are going to receive. Even though you enable this warning setting on, if your friend’s setting is not on, they will not be notified if the messages they are sending to you are intercepted.This unintentional secret door is called a ‘user friendly design choice’ by WhatsApp. It is such a user friendly design choice it is government agents friendly as well. I can’t imagine how many diplomats already delivered confidential messages to enemy agencies using WhatsApp. Diplomats in Brussels wake up and smell the coffee…

“Rail travel at high speeds is not possible because passengers, unable to breathe, would die of asphyxia.”-Dionysius Lardner, Professor of Natural Philosophy and Astronomy at University College, London, 1830It hurts my heart to see an esteemed university publish such a regrettable article.  It is also shocking that there was no empirical based insight published, just agenda ladened conjecture.  In some ways I am not surprised.  Academia has misunderstood the payments industry for over 50 years and I have tried and have been successful to help quite a number of well known professors understand the details.  However, if one were to go by the postulations some Professors have presented over the years, the payments industry should not exist.   There is much to learn from these insights and surprisingly many of them were adopted by some payment startups, advisors, board members and VCs.   I will address the idle conjecture from this article, section by section:Apple Pay’s Technology Adoption ProblemApple wants to convert your iPhone into a digital wallet with Apple Pay. Professors Benjamin Edelman and Willy Shih assess its chances for success and wonder if consumers have a compelling reason to make the switch.This is a mostly correct insight.  It may turn out to be ironic wording on the part of the author.    To be clear, no one needs to “switch”.On the eve of debuting its digital payment system, Apple Pay, two Harvard Business School professors think the Cupertino company will have trouble coming up with an equally compelling message to drive sales of a service that allows you to pay at the retail counter with a swipe of an iPhone.No iPhones are “swiped” during a transaction, they are held at short distance for a few seconds in front of a customer facing terminal. "What does it do for me as a consumer?" asks Associate Professor Benjamin Edelman. “Why would I want to trade for something that already works [e.g. credit and debit cards], something that doesn't complain when it gets wet in the rain, something that doesn't complain when I launder my pants?"Why would I want to trade in an iPod, for something that already works, the Sony Walkman and use the cassette tapes that already work.  This is a comment that shows a professor that truly does not understand the history of technology. Especially, he adds, when those cards give users and additional 1 or 2 percent off the purchase price. “I think Apple has its work ahead in convincing thoughtful and potentially skeptical customers," says Edelman.There is little that one can draw from this passage.  There is no loss of 1 or 2 percent if the cards offered them before, they will be offered in the exact same manner via Apple Pay. ON WITH THE SHOWReports say Apple will roll out the digital payment service later this week, with perhaps more details coming at a press conference Thursday. But will it catch on, especially when several other similar services with big name sponsors such as Google have failed to gain much traction?The element that was overlooked by this professor is the fact that very little is similar to the business processes and business relationships Apple used in relationship to Google.   Apple choose wisely to work with every element of the existing payments ecosystem.  History will show, and likely this university will teach, that this was the primary premise that made Apple Pay the largest change since the invention of the magnetic stripe. Apple has a chicken-and-egg game to solve. Consumers won't use the service unless they are in use at a compelling number of stores. But merchants won’t install the expensive near field communications readers used by Apple Pay unless consumer demand is high.First off, Apple must convince merchants to adopt its service, says Willy Shih, the Robert and Jane Cizik Professor of Management Practice.“I THINK APPLE HAS ITS WORK AHEAD IN CONVINCING THOUGHTFUL AND POTENTIALLY SKEPTICAL CUSTOMERS”Only about 10 percent of retailers use NFC readers, and at least one retailer—Best Buy—stopped using them because they were too expensive. Officials with both Best Buy and Walmart have said the retailers have no plans, at least right now, of accepting the new payments technology in their stores.There will always be a “Chicken / Egg” issue with any system that would require equipment upgrades.   However this article assumes over 200,000 of the most popular businesses in the US is not “a compelling number of stores”.  It took 30 years for Visa and MasterCard to have over 200,000 businesses.   It took over 5 years for Discover to have over 200,000 business locations.   The professors did not even do a single empirical study to gain insights about the number of actual businesses and the demand to upgrade.   I am performing these studies and can say that early results point of almost 300,000 locations and a demand that has shot up by over 3,000% and growing among small to large businesses.Thus Apple will not have “work” to convince merchants, the huge drive is coming from merchants and banks wanting to implement the service.Best Buy stopped using NFC for only one reason, they were not paying PIN based debit rates for these transactions and Apple is on the way to get these types of cards to be confirmed using biometric PINs.  Shih believes merchants who consider adopting Apple Pay will naturally wonder: What do we get out of this? And they will specifically want to know if they will be asked to pay higher fees than credit card companies are charging?The data that Professor Shih has is invalid.  The merchant is paying the exact same rate as with any other credit card.   What they get out of it is manifold but no one can argue that the increase in speed is one foundational benefit. "Consumers might be motivated to do it, but if I don't have the merchant side in place, it doesn't matter," Shih says. "The merchants certainly aren't going to be motivated if the economic model is less favorable than today. It’s a complicated puzzle."The data that Professor Shih has is invalid.   The economic model is not a “complicated puzzle to anyone other then Professor Shih.Apple has touted that Apple Pay will be supported by several leading retailers, including Bloomingdale's, McDonald's, and Macy's—and that it will work at about 220,000 merchant locations across the United States that have enabled contactless payments. But some analysts believe that's a small number compared with the nine million US merchants that currently accept credit cards. In short, Apple has a long way to go to knock off the established credit card system, Shih says.There is some valid information here.  However 80% of the dollar volume in retail payment card sales come from 20% of merchants.  Apple will have coverage of about 70% of these merchants by year end.  My research suggests that a tremendous number of smaller merchants will fill in these numbers as 2015 winds out. "Ecosystems are very delicately balanced, and the current payment system represents a balance that has resulted from 40 years of evolution. There's a lot of inertia around that," Shih says. "You can have great technology, but you really have to line up the complementary assets so all the pieces play with you and they are motivated to make it work. At the end of the day, Apple is going to have to make the economics work for everybody. That is a hard job.”Professor Shih is still functioning on invalid data about the “economics”.  The economics are exactly the same.DO CUSTOMERS CARE?Which brings us to the customer side of the chicken-and-egg conundrum. Millions of shoppers have used cards for years, with little hassle. Edelman points out that people will continue to carry cards even if digital payments gain some traction, so the barrier to overcome for mass acceptance is even higher.Millions of people used payment cards every day at Starbucks.  But somehow  6 million weekly transactions in the U.S a full 15% of transactions made at the U.S. Starbucks-operated stores are made on the Starbucks wallet.  The barriers these users overcome are huge, they have to buy credits using a payment card to even operate the wallet, yet this barrier is overcome 6 million times per week.Edelman has studied Bitcoin, a software-based online payment system, and he sees similarities between technology adoption roadblocks Bitcoin has encountered and issues Apple Pay is likely to face."Apple Pay has the same problems as Bitcoin: There's no reason for the regular consumer to use it," he says. “Why would a consumer want to make a $100 purchase with Bitcoin when the consumer can pay with a credit card and get 2 percent cash back?"There is absolutely no comparison to Apple Pay and Bitcoin.  Professor Edelman is also operating on invalid data.  The payment card that pays 2% back will continue to pay 2% back with Apple Pay.In addition to the limited number of merchants, Apple Pay appears to be limited to users of the latest iPhone 6, iPhone 6 Plus, and Apple Watch—which leaves out many consumers with older iPhones or Android models.“Apple might be hamstrung by an incompatibility issue that the company intentionally introduced," Edelman says.The system works on iPhone 6 series phones.  There is no doubt that there will be similar Android initiatives.  The picture is very clear, if you have an iPhone 6 series phone, it works.  This is not an incompatibility issue. Shih agrees that selling technology is tricky in a market full of incompatible products.Yes, yes it is."We're in a period now where you see this design competition with competing offerings, and on top of that, you have a platform competition where everyone has their network effects," he said. "It's like PlayStation versus Xbox. The technology convergence has brought us to a place where people are scrambling to come up with a new platform and trying to become the new dominant design.”Great insight about video game platforms.  However they have no analogy with the subject of Apple Pay.Other companies that have attempted mobile payments have run into similar problems. Google Wallet was limited by its compatibility with different types of phones and cellular networks. And Softcard, which was backed by major wireless carriers, has seen little traction with its mobile wallet for similar reasons.This is correct.  This is one of the most accurate insights from these professors.   The destiny of Google Wallet was never in the hands of Google and thus it contributed to the failure of the system.  This is not the case with Apple Pay.  PITCHING SECURITYOne marketing pitch Apple is sure to try out with potential users is security, especially after notable bsignNowes at Home Depot and Target. When a customer pays with an iPhone, cashiers won't see the consumer's name, credit card number or security code because Apple uses a fingerprint reader on its recent iPhones to confirm identities. And when consumers add a credit or debit card with Apple Pay, the card number is not stored by Apple—instead, Apple provides a unique device account number for each transaction. In addition, the company says it won’t collect consumers' purchase history.Very accurate assertion.Edelman questions whether addressing security and privacy will be enough of a carrot to wean consumers off of their beloved plastic. Hesays other companies have tried to market the security angle, including the RevolutionCard, a PIN-based credit card that had no name, signature, or account number on it so that if it got lost or stolen, it couldn't be used unless the PIN was known. "It was stillborn," Edelman says. "It didn't work as a feature set. No one cared.”Professor Edelman is partly correct about the failure of  Steve Case’s Gratis Card and The Revolution Money Card.   However the professor is operating on invalid data.  Apple Pay is not a card replacement.  Apple Pay is a security wrapped around the existing payment card issuer relationship.“APPLE PAY HAS THE SAME PROBLEMS AS BITCOIN. THERE’S NO REASON FOR THE REGULAR CONSUMER TO USE IT”Even recent high-profile data bsignNowes have not led consumers to abandon credit cards in signNow numbers. "Security doesn't work for the thoughtful consumer," Edelman says. "(Data bsignNowes) mostly mean inconvenience for the consumer because the losses are really borne by banks, merchants, and credit cards, not by consumers."Besides, Shih wonders whether data will be any safer with the Apple Pay system.I think Professor Shih may need to conduct a study on how the Target bsignNow impacted consumers.  I have not conducted a deep study but can state clearly that some consumers had their bank account zeroed out in the early days of the bsignNow and the banks were not crediting back the transaction that appeared “valid” from debit card bsignNowes.  I know of a case where a single mom had missed rent and food because of the missing funds in her checking account for days.  Although this is anecdotal, there are many examples vetted by the media. I would also ask Professor Shih  to speak with any merchant that has been a victim of a major bsignNow about how systems like Apple Pay would have saved them millions of dollars in fines and replacement costs to card holders. "The fingerprint reader generating a unique code is pretty smart," he acknowledges. "But it electronically seems to do the same thing as a PIN code. And to the extent that the code goes into the existing payment network that's still not secure, have we really accomplished anything?"TouchID is far and away more secure then a 4 digit PIN code.   The math is quite simple.   But just the logic, it take very little time to guess a PIN number.  It takes a great deal of time to try to fake a finger print that is acceptable to TouchID.  In many cases it is impossible to fake a fingerprint unless you have intimate access to the target.  Thus a faster way to steal money is a PIN number and not a finger print. CAN YOU PAY ME NOW?Other technical questions remain. Edelman wants to know whether Apple Pay will work if the phone isn’t charged, or in areas with poor cell reception?This would be better addressed by studying the technology and not using a  a guessing game.   Apple Pay will work with zero cell or WiFi reception.  Apple Pay will work with a low battery.  Apple Pay will stop working if there is no way to power on the iPhone.  Apple may release more details tomorrow, so time will tell whether the company will address some of the system's potential shortcomings—and perhaps more important, whether regardless of any shortcomings, merchants and consumers will embrace this new mode of payment. Either way, even if Apple stumbles with its mobile wallet, the company will likely survive the reputation hit.Yes, they addressed the shortcomings.  Apple announced that instead of 7 banks supporting Apple Pay payment cards, there are now over 500."Any failure Apple experiences here will be more than offset by the legions of fans that like their other stuff," Edelman said. “I'm not losing any sleep for Apple."I think Professor Edelman can sleep soundly.    He has articulated how some academics, even notable academics are all too human.  We are fallible.   I hope that history is kind with these Professors.

Some of the frequently asked Interview questions for java developers are:1   What is an object ? 2   What is method overriding in java ? 3   What is super keyword in java ? 4   What is method overloading in java ? 5   What is difference between c++ and Java ? 6 What is JIT compiler ? 7   What is bytecode in java ? 8   Difference between method overloading and method overriding in java ? 9   Difference between abstract class and interface ? 10   Why java is platform independent? 11 Difference between this( and super( in java ?12 How to call one constructor from the other constructor ? 13 what are static blocks and static initalizers in Java ? 14 What is method in java ? 15 What is constructor in java ? 17 Difference between Character Constant and String Constant in java ?18 Why main( method is public, static and void in java ? 19 Explain about main( method in java ? 20 What is difference between length and length( method in java ? 21   What  is ASCII Code? 22 What is Unicode ? 23 What are constants and how to create constants in java? OOPS24 Explain about object oriented programming and its features? 25 What is Abstraction? 26 What is Encapsulation? 27 What is the difference between abstraction and encapsulation? 28 List out benefits of object oriented programming language? 29 Differences between traditional programming language and object oriented programming language? 30 What is Inheritance? 31 What is Polymorphism? 32 How does Java implement polymorphism? 33 Explain the different forms of Polymorphism 34 What is runtime polymorphism or dynamic method dispatch? 35 What is Dynamic Binding? 36 What is method overloading? 37 What is method overriding? 38 What are the differences between method overloading and method overriding? 39 Can overloaded methods be override too? 40 Is it possible to override the main method? 41 How to invoke a superclass version of an Overridden method? 42 What is super? 43 How do you prevent a method from being overridden? 44 What is an Interface? 45 Can we instantiate an interface? 46 Can we create an object for an interface? 47 Do interfaces have member variables? 48 What modifiers are allowed for methods in an Interface? 49 What is a marker interface? 50 What is an abstract class? 51 Can we instantiate an abstract class? 52 What are the differences between Interface and Abstract class? 53 When should I use abstract classes and when should I use interfaces? 54 When you declare a method as abstract, can other nonabstract methods access it? 55 Can there be an abstract class with no abstract methods in it? 56 What is IS-A relationship  in java?57 What is HAS A relationship in java?58 Difference between IS-A and HAS-A relationship in java?59 Explain about instanceof operator in java?60   What does null mean in java?61   Can we have multiple classes in single file ?62   What all access modifiers are allowed for top class ?63 What are packages in java?64   Can we have more than one package statement in source file ?65   Can we define package statement after import statement in java?66 What are identifiers in  java?67 What are access modifiers in java?68   What is the difference between access specifiers and access modifiers in java?69   What access modifiers can be used for class ?70   Explain what access modifiers can be used for methods?71   Explain what access modifiers can be used for variables?72   What is final access modifier in java?73   Explain about abstract classes in java?74 Can we create constructor in abstract class ?75   What are abstract methods in java?Type Casting      76 What is TypeConversion? 77 Explain Implicit Conversion/ Widening/Automatic Type Conversion? 78 What is Explicit Conversion/Narrowing/Casting? 79 Can a double value be cast to byte? How to cast double value to byte with help of the example? 80 Can a Boolean primitive value to be converted to any other primitive in java? 81 What is autoboxing and autounboxing? 82 What are advantages of autoboxing and autounboxing? 83 How to cast objects or what is object casting? 84 What is upcasting or downcasting? Exception Handling85   State some situations where exceptions may arise in java?86   What is Exception handling in java?87    What is an eror in Java?88   What are advantages of Exception handling in java?89   In how many ways we can do exception handling in java?90   List out five keywords related to Exception handling ?91   Explain try and catch keywords in java?92   Can we have try block without catch block?93    Can we have multiple catch block for a try block?94   Explain importance of finally block in java?95   Can we have any code between try and catch blocks?96   Can we have any code between try and finally blocks?97   Can we catch more than one exception in single catch block?98   What are checked Exceptions?99   What are unchecked exceptions in java?100   Explain differences between checked and Unchecked exceptions in java?101 What is default Exception handling in java?102   Explain throw keyword in java?103   Can we write any code after throw statement?104 Explain importance of throws keyword in java?105 Explain the importance of finally over return statement?106 Explain a situation where finally block will not be executed?107   Can we use catch statement for checked exceptions?108   What are user defined exceptions?109   Can we rethrow the same exception from  catch handler?110   Can we nested try statements in java?111 Explain the importance of throwable class and its methods?112 Explain when ClassNotFoundException will be raised ?113 Explain  when NoClassDefFoundError  will be raised ?Nested Class & Inner Class114 What are inner classes or non static nested classes in java? 115   Why to use nested classes in java? 116   Explain about static nested classes in java? 117 How to instantiate static nested classes in java? 118   Explain about method local inner classes or local inner classes in java? 119 Explain about features of local inner class? 120 Explain about anonymous inner classes in java? 121 Explain restrictions for using anonymous inner classes? 122   Is this valid in java ? can we instantiate interface in java? 123 Explain about member inner classes? 124 How to instantiate member inner class? 125 How to do encapsulation in java? 126 What are reference variables in java ? 127 Will the compiler creates a default constructor if I have a parameterized constructor in the class? 128   Can we have a method name same as class name in java? 129   Can we override constructors in java? 130 Can Static methods access instance variables in java? 131 How do we access static members in java? 132    Can we override static methods in java? 133 Difference between object and reference? 134 Objects or references which of them gets garbage collected? 135 How many times finalize method will be invoked ? who invokes finalize( method in java?136 Can we able to pass objects as an arguments in java? 137 Explain wrapper classes in java? 138 Explain different types of wrapper classes in java? 139 Explain about transient variables in java? 140 Can we serialize static variables in java? 141   What is type conversion in java? 142   Explain about Automatic type conversion in java? 143 Explain about narrowing conversion in java? 144 Explain the importance of import keyword in java? 145 Explain naming conventions for packages ? 146 What is classpath ? 147 What is jar ? 148 What is the scope or life time of instance variables ? 149 Explain the scope or life time of class variables or static variables? 150 Explain scope or life time of local variables in java? 151   Explain about static imports in java? 152 Can we define static methods inside interface? 153 Define interface in java? 154 What is the purpose of interface? 155 Explain features of interfaces in java? 156 Explain enumeration in java? 157 Explain restrictions on  using enum? 158 Explain about field hiding in java? 159   Explain about Varargs in java? 160 Explain where variables are created in memory? 161 Can we use Switch statement with Strings? 162 In java how do we copy objects? Theads163 What is thread in java? 164   Difference between process and thread? 165   What is multitasking ? 166   What are different types of multitasking? 167   What are the benefits of  multithreaded programming? 168   Explain thread in java? 169   List Java API that supports threads? 170   Explain about main thread in java? 171   In how many ways we can create threads in java? 172   Explain creating threads by implementing Runnable class? 173 Explain creating threads by extending Thread class ? 174 Which is the best approach for creating thread ? 175   Explain the importance of thread scheduler in java? 176   Explain the life cycle of thread? 177   Can we restart a dead thread in java? 178   Can one thread block the other thread? 179 Can we  restart a thread already started in java? 180 What happens if we don’t override run method ? 181   Can we overload  run( method in java? 182 What is a lock or purpose of locks in java? 183   In how many ways we can do synchronization in java? 184   What are synchronized methods ? 185 When do we use synchronized methods in java? 186   When a thread is executing synchronized methods , then is it possible to execute other synchronized methods  simultaneously by other threads? 187 When a thread is executing a synchronized method , then is it possible for the same thread to access other synchronized methods of an object ? 188 What are synchronized blocks in java? 189   When do we use synchronized blocks and advantages of using synchronized blocks? 190   What is class level lock ? 191   Can we synchronize static methods in java? 192   Can we use synchronized block for primitives? 193   What are thread priorities and importance of thread priorities in java? 194   Explain different types of thread priorities ? 195   How to change the priority of thread or how to set priority of thread? 196   If two threads have same priority which thread will be executed first ? 197 What all methods are used to prevent thread execution ? 198 Explain yield( method in thread class ? 199   Is it possible for yielded thread to get chance for its execution again ? 200 Explain the importance of join( method in thread class? 201   Explain purpose of sleep( method in java? 202   Assume a thread has lock on it, calling sleep( method on that thread will release the lock? 203 Can sleep() method causes another thread to sleep? 204 Explain about interrupt() method of thread class ? 205 Explain about interthread communication and how it takes place in java? 206 Explain wait() , notify() and notifyAll() methods of object class ? 207 Explain why wait(), notify() and notifyAll() methods are in Object class rather than in thread class? 208 Explain IllegalMonitorStateException and when it will be thrown? 209   when wait(), notify(),notifyAll() methods are called does it releases the lock or holds the acquired lock? 210   Explain which of the following methods releases the lock when yield(), join(),sleep(),wait(),notify(), notifyAll()methods are executed?211   What are thread groups? 212 What are thread local variables ? 213 What are daemon threads in java? 214 How to make a non daemon thread as daemon? 215 Can we make main() thread as daemon?Collection Framework216 What is collection ?217 Difference between collection, Collection and Collections in java?218 Explain about Collection  interface in java ?219 List  the interfaces which extends collection interface ?220 Explain List interface ?221 Explain methods specific to List interface ?222 List implementations of List Interface ?223   Explain about ArrayList ?224 Difference between Array and ArrayList ?225   What is vector?226 Difference between arraylist and vector ?227   Define  Linked List and its features with signature ?228   Define Iterator and methods in Iterator?229 In which order the Iterator iterates over collection?230   Explain ListIterator and methods in ListIterator?231 Explain about Sets ?232 Implementations of Set interface ?233   Explain HashSet and its features ?234 Explain Tree Set and its features?235 When do we use HashSet over TreeSet?236 What is Linked HashSet and its features?237 Explain about Map interface in java?238 What is linked hashmap and its features?239   What is SortedMap interface?240   What is Hashtable and explain features of Hashtable?241 Difference between HashMap and Hashtable?242 Difference between arraylist and linkedlist?243 Difference between Comparator and  Comparable in java?244 What is concurrent hashmap and its features ?245 Difference between Concurrent HashMap and Hashtable and collections.synchronizedHashMap?246 Explain copyOnWriteArrayList and when do we use copyOnWriteArrayList?247 Explain about fail fast iterators in java?248 Explain about fail safe iterators in java?Serialization249 What is serialization in java? 250 What is the main purpose of serialization in java? 251 What are alternatives to java serialization? 252 Explain about serializable interface in java? 253 How to make object serializable in java? 254 What is serial version UID and its importance in java? 255 What happens if we don’t define serial version UID ? 256 Can we serialize static variables in java? 257 When we serialize an object does the serialization mechanism saves its references too? 258 If we don’t want some of the fields not to serialize How to do that? 259 Explain importance of object class in java? 260 Explain purpose of object class or why object class is super class for all java classes? 261 Explain Object class methods? 262 List methods which can be overrided from Object class? 263 Explain purpose of toString( method in java?Strings 264 Explain Strings in java?265 Difference between Strings and Character Arrays in java?266 Explain importance of String class in java?267 In how many ways we can create Strings in java?268 Explain how to create Strings using String literal and advantages of creating Strings using String literal?Class Loaders 269 What are classloaders and different types of class loaders in java?270 What is BootStrap class loader and how does it works?271 What is Extensions class loader and how does it works?272 What is application class loader and how does it works?273 When an object becomes eligible for garbage collection?274 Who performs garbage collection?275 When does garbage collector run?276 Which algorithm garbage collector uses to perform garbage collection?277 List out different garbage collection algorithms?278 Can we force JVM for garbage collection?279 How to request jvm to perform garbage collection operation?280 Explain the purpose of finalize method in relation to Garbage collection?281 How many times finalize method is called on an Object?282 Once an object is garbage collected can it become signNowable again?283 How to write a code that makes an object eligible for garbage collection?

When it comes down to choosing a good solution to manage your documents, whether you’re an individual, or part of a company, there are a few things to consider, and it basically boils down to what you need the software to accomplish, how much automation you want, how easy do you want it to be.A good all around option I’d suggest checking out it Kdan Document 365. It has some nice features to help you manage your PDFs (editing, signing, etc.,) and other kinds of documents you might be working with. If you’re part of a company, it’s easy to share and collaborate on projects/documents/presen...

Since 1990, I’ve been studying the confidentiality of the messaging systems on computers and mobile devices.It was obvious that the electronic forums, emails and SMS messages could easily be intercepted by 3rd parties. Expecting the service providing companies to develop and implement confidentiality protocols were unrealistic. There were never a general consensus about the need for confidentiality or inter-service protocol development.With the discouragement of the governments many computer scientists shied away from creating software to keep communication confidential between parties.Many spy movies showed advanced technologies to keep the communication between spies and their organizations. The most famous being the Enigma machine used by the Germans during the World War 2. British scientist Alan Turing was the one to develop an early version of today’s computers to solve the mystery of the Enigma machine. Like every visionary he had serious problems with the establishment. After the government discovering that he was gay, he was given 2 options. First option was jail time until he turned heterosexual, or chemical castration. Poor Turing chose the second option and after a while he committed suicide. Every cryptologist today remembers to what happened to the first representative of this science.Without getting into the technological terms (they are all available on Wikipedia) the best way to keep conversation confidential is to use a code book between 2 (or more, but more on that later) parties. A code book is a simple definition and a list of codes that is shared between the parties and each code is used only once. Unless the code book is compromised this method of communication privacy is bullet proof. There is no computer in the world, and there won’t be any in the future that can figure out what the communication is. The only method would be the old school spying on the parties who are communicating between each other.If I need to give an example for the method above, it would be like, let’s choose a newspaper that is accessible to both parties. That will be our message base.Let’s define a codebook now:First code in the book is3–4,6–7,1–2 and repeats itselfsecond code is5–7,3–1,8–5,4–2 and repeats itselfSo let’s say I send you a message today like20,42,15,5,8,67,23,56,12,43,13,11,10Since it is our first message exchange you will use the first code in the book. Also our message base is only known to us which also makes it even more difficult for others to understand the secret message I just sent you.To understand the message, here is what you do: you pick up today’s New York Times which is the newspaper we agreed to use.Take the first number in the secret message which is 20, then look in the codebook for the first code which is 3–4. You go to the 3rd page find the 4th paragraph and get the 20th character and repeat this process for each number in the secret message I sent.Let’s say MI6 is trying to intercept the message, which they do because I sent the message by email or SMS or event with both to you.All they have is 20,42,15,5,8,67,23,56,12,43,13,11,10 and they have no idea what it means. They don’t know which text source we used, which was New York Times and they don’t know the code we used for that message which was 3–4,6–7,1–2. We can even make this more difficult, for each day of the week we use a different newspaper that we agree upon.And let’s say MI6 figures out which newspaper we use for each day, let’s say they even figure out our code mechanism which is the page, paragraph and character to decode the secret message.As long as we use each line of code only once and never repeat used codes, there is virtually no way that MI6 to figure out our conversation. Except of course sending their double o agent to one of us and beating us in the head with an iron bar which would make us sing like a bird and spill all the secrets.As you can see in the example an iron bar, strategically placed on your head with a moderate blow would break all the code we established.That reality aside, if I whisper to your ear the newspaper names and hand you a piece of paper with a list of codes which I also have the same copy, until ve run out of codes there is no way our communication can be interpreted when intercepted.The difficulty in this type of message confidentiality is sharing and keeping a piece of paper with a list of codes and do the code exchange again when the list of codes are depleted and never use a code again.When this is not possible for practical reasons like distance between parties or the number of messages exchanged being too high and frequent the methodology used is computer based encryption (ensuring the confidentiality of communication between parties) of messages.This is also not so unlike what we did in the first example. To create our never ending codes is that for each message we exchange we use 3 constants. You have a master key, a public key and we agree on a mathematical formula which is very very difficult for the computer to solve. The difficulty here ensures that the time to try every combination of variables (without the master key) for the formula is so long, it practically makes it impossible for others to guess our code list.In this method I also have a master key and a public key. To solve the issue of keeping a list of established codes and communicating that between parties we freely exchange our public keys with everyone and when I’m sending you a message, I use your public key (any of my keys except generating a special signature with my private key so that you can validate with my public key that ensures the message has originated really from me) to create a confidential message. When you receive it by email, SMS or regular post mail, you use your private key which can only find out the contents of the confidential message. And since we are talking about computer systems, we protect our private keys with passwords.I don’t like using names given by computer engineers or any other technical person but for the sake of clarification this master/public key and an established algorithm to use is called public private key cryptology.Another term I don’t like is ‘end to end encryption’. This is to confirm that the cryptology method used can not be intercepted by other parties and only the recipient can understand the contents of the message.One company who has developed an implementation of end to end encryption is Open Whisper Systems. They named their product ‘Signal’ which is a platform and also the name of their app on iOS and Android. Their product uses this public private key cryptology to ensure the text and voice communications between parties to stay confidential. Supposedly the infamous NSA whistle blower Edward Snowden uses their app and he considers it quite good.Now let’s circle back to the WhatsApp security issue. WhatsApp is using the protocol established by the Open Whisper Systems for their public private key protected communications (audio, video and text messages).The problem is the user friendliness of the Signal app is not good. There are certain times that these public and private keys have to be changed. 2 example of those times is if you change your phone or uninstall / reinstall your app (whichever app you are using, Signal or WhatsApp)To test the user friendliness of Signal App’s handling the change of the key pairs (public private key combinations) I used my regular human guinea pig Riz. It was very difficult for me to explain what he has to do and also to find the location of the menu items were horribly difficult. After cursing at me and the app designers many times Riz completed the approval of the new key exchange between us so we could communicate again.Let’s have a look into how WhatsApp has implemented this renewal of key pairs between users. Since authenticity of a user can only identified by trusting their private key signed signature and for the likely case of the user have a new phone or has reinstalled the WhatsApp App, WhatsApp servers keep a copy of the secret message until the recipient downloads it. Now let’s say that you sent me a message while I was offline and I changed phones meanwhile. When I get that message from you what the Signal app does is, it warns me and it won’t let you communicate with you until I approve your new public key (in the style of a combined public keys of both parties because there is only one code that needs to be verified on both ends). Instead of asking user to do the verification what WhatsApp does it re-encrypts your message with my new key again (in their explanation by asking your WhatsApp to keep that message in memory in encrypted form and first decrypt then re-encrypt the same message with my new public key) without asking neither of us to re-confirm the identity of both parties.This technically opens up a backdoor for intelligence agencies to decrypt the messages between parties.How does that happen? WhatsApp confirms App installation by SMS confirmation. Let’s say I want to intercept your WhatsApp messages. I send a team in a delivery van which looks like a repair van but which has a mobile communication signal jammer to your home address. The jamming is smart enough to make your phone think it is still in network coverage so you don’t suspect a thing unless you try to make a call which will look like mobile network is crowded and unavailable. While I knock your phone off the network I can do 2 things, I can either intercept any SMS messages which comes your way in my service van, or give a court order to the mobile phone company to give me a copy of your SMS messages in real time.Then I install WhatsApp on a new phone, enter your phone number as my number and receive a copy of the SMS confirmation with the verification number and enter it in WhatsApp. From that moment on I will receive any waiting (since I knocked you off mobile network) and any news messages WhatsApp users send to you.Intentional or unintentional this is a secret door that can be easily used by government agencies.If I used the above technique to intercept messages between Signal users, what would happen were to be, first I couldn’t receive any messages waiting in the cloud because Signal does not keep messages in the cloud, when you are offline, the message waits in the sender’s Signal App. When the sender tries to send a new or resend the unsent message to you, my new installation of Signal app on my government agency phone will inform your friend, the sender that I’ve changed our shared agreed secret code and asks your friend if s/he wants to approve this new installation on the other end by confirming the new shared secret code with you. When s/he calls you on your landline, you say you haven’t installed a new WhatsApp on your phone or changed phones, you both understand that there is another party in between trying to intercept your messages.Now, WhatsApp says that there is an option in their App, under Settings / Account / Security / Show Security Notifications which is by default off. If you turn this ON then their claim is you will receive notifications when a contact’s security code has changed. They don’t say if the messages will still be delivered in spite of a security notification or not. They add that ‘The messages you send your calls are encrypted regardless of this setting, WHEN POSSIBLE’. I capitalized the last 2 words, what the heck ‘WHEN POSSIBLE’ mean? They also do not say anything about the messages you are going to receive. Even though you enable this warning setting on, if your friend’s setting is not on, they will not be notified if the messages they are sending to you are intercepted.This unintentional secret door is called a ‘user friendly design choice’ by WhatsApp. It is such a user friendly design choice it is government agents friendly as well. I can’t imagine how many diplomats already delivered confidential messages to enemy agencies using WhatsApp. Diplomats in Brussels wake up and smell the coffee…